Reading images
Models that can see analyse photos, screenshots and scanned pages directly. This page shows how to attach images, what Custodos does with them before sending and when an image is not accepted.
Last checked on 28 September 2026
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Attaching an image
You attach images like any other file: through Add and Attach file, by dragging them onto the chat or from the clipboard. That way you can paste a screenshot straight into the message field. The card above the message field then shows Image.
Custodos accepts PNG, JPEG, WebP and GIF. Images in other formats are converted to JPEG by your browser before upload, as long as it can open them, for example HEIC photos from an iPhone in Safari. If that does not work, Custodos turns away formats such as HEIC, TIFF or SVG with a hint to save the image as PNG or JPEG. You can send an image without any text. Usually, though, a sentence on what the model should do with it helps, such as “Turn the table in this photo into a list”.
What Custodos does with an image
Before an image is stored, Custodos prepares it the same way for every model. Images that already fit stay unchanged.
- The longest edge is scaled down to at most 1,568 pixels. The models would scale larger images down anyway.
- The orientation is corrected, so pages photographed upright arrive the right way round.
- Metadata is removed, including the GPS location many phones store in photos.
- The image is stored as PNG or JPEG.
Limits for images
Each image belongs to the message you sent it with. This lets the model tell which screenshot came before and which came after. Like any attachment, the image stays available for the whole chat, see Attaching files.
| Limit | Value | What happens |
|---|---|---|
| Size per image when uploading | 20 MB, as for any file. Your browser usually scales large photos down before upload. | The image is larger than 20 MB. |
| Images per chat | 30 | This chat already holds 30 images. Start a new chat for more. |
| Images the model sees per message | up to 20, newest first | Older images stay in the chat. The model is told only their file names. |
Models that cannot read images
Not every model can see images. If one of these is selected, Custodos warns you next to the card: … cannot read images. Attached pictures stay out of the request and the model is told only their file names. The model's name stands in place of the dots.
In that case, switch to a model that reads images in the message field. The table under Models shows which ones do.
When images are not accepted
Custodos cannot check the content of an image for personal data. Where such a check is promised, it therefore turns images away.
| Situation | Message | What you can do |
|---|---|---|
| Your admin has blocked images in the data-protection settings, for example with the Strict protection level | Images are blocked in this workspace by its data-protection settings. | An admin can allow images under Settings › Data protection › Categories and rules › Images. Admins see a notice with a link to the setting instead of this message. |
| The chat runs in security mode | Images cannot be attached in security mode, because image content cannot be pseudonymised. | Use a regular chat for images. |
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